﻿/*
Copyright 2010 Matías Fidemraizer (www.matiasfidemraizer.com).

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

using System;
using System.Reflection;

namespace Comkarl.Architecture.Patterns.Singleton
{
    /// <summary>
    /// Represents the base class for a singleton.
    /// </summary>
    /// <typeparam name="TConcrete">
    /// The concrete type of singleton.
    /// </typeparam>
    public abstract class Singleton<TConcrete> : SinglePatternInstance
        where TConcrete : Singleton<TConcrete>
    {
        /// <summary>
        /// Default constructor.
        /// </summary>
        protected Singleton()
        {
        }

        /// <summary>
        /// Static constructor.
        /// </summary>
        static Singleton()
        {
            // Creates an instance of concrete singleton type.
            current = (TConcrete)typeof(TConcrete).GetConstructor
            (

                BindingFlags.Instance | BindingFlags.NonPublic,
                Type.DefaultBinder,
                new Type[] { },
                null
            ).Invoke(null);
        }

        private static TConcrete current;

        /// <summary>
        /// Gets the instance.
        /// </summary>
        public static TConcrete Current
        {
            get
            {
                return current;
            }
        }
    }
}